Catheters of many types and configurations have been known and have been utilized for a number of years. Venous catheters function to carry fluids into and out from the vein of a patient. One problem associated with venous catheters is the physical discomfort to the patient caused by the insertion of the catheter into the vein and the maintenance of the catheter in the patient for a period of time. Another problem associated with venous catheters is one of infection to the patient. These problems become magnified when a number of venous catheters are inserted either at the same time or over a period of time. An overall solution, therefore, is to arrive at a venous catheter having multi-lumens (i.e., fluid carrying passageways) in a single catheter. Utilization of a catheter with multi-lumens would minimize the problems associated with patient discomfort and the risk of infection.
A prior art search, conducted by the inventor of the present invention, disclosed various types of multi-lumen catheters having various functions. The results of this search are set forth as follows:
______________________________________ Inventor U.S. Pat. No. Issue Date ______________________________________ H. H. Khalil 3,359,974 Dec. 26, 1967 Ballard 3,055,361 Sept. 25, 1962 L. J. Bielinski 3,437,088 April 8, 1969 Shepherd et al 3,566,874 March 2, 1971 Jose M. R. Delgado 3,640,269 February 8, 1972 T. H. Shepherd 3,695,921 October 3, 1972 Norton et al 3,726,281 April 10, 1973 Schlesinger 3,805,794 April 23, 1974 Spinosa et al 3,815,608 June 11, 1974 Long 3,867,945 February 25, 1975 Ross 3,885,567 May 27, 1975 Blake et al 3,995,623 Dec. 7, 1976 Thow 4,057,065 Nov. 8, 1977 Howes 4,072,146 Feb. 7, 1978 Sorenson et al 4,099,528 July 11, 1978 Frisch 4,100,246 July 11, 1978 McWhorter 4,106,509 August 15, 1978 Kenigsberg 4,168,703 Sept. 25, 1979 Betancourt 4,180,076 Dec. 25, 1979 Grimsrud 4,203,436 May 20, 1980 Sagae et al 4,217,895 August 19, 1980 ______________________________________
The 1978 patent issued to Howes (U.S. Pat. No. 4,072,146) relates to a venous catheter device having a plurality of independent fluid conveying lumens housed within a single catheter. The multi-lumen catheter of Howes is designed to have an outer diameter slightly smaller than the inner diameter of the insertion needle so that the catheter can be inserted through the needle. Each of the independent lumens are encased within an outer tube.
In operation, the Howes catheter permits two or more fluids to be infused simultaneously into the blood stream at discrete spacings of at least one centimeter. This prevents any mixing problem.
The 1978 patent issued to Sorenson et al (U.S. Pat. No. 4,099,528) relates to a double lumen cannula for separately injecting fluids into the blood vessel or withdrawing fluids from a blood vessel. The double lumen represents concentric passageways.
The 1976 patent issued to Blake et al (U.S. Pat. No. 3,995,623) relates to a multi-lumen catheter containing a number of lead wires and a permanent stylet wire of graduated stiffness.
The patents issued to Shepherd et al (U.S. Pat. No. 3,566,874), Shepherd et al (U.S. Pat. No. 3,695,921), Norton (U.S. Pat. No. 3,726,281), Long (U.S. Pat. No. 3,867,945) and Spinosa (U.S. Pat. No. 3,815,608) all relate to multi-lumen catheters of differing configurations for use as ureteral catheters. In all of these embodiments, a central lumen is provided with one or more lumens disposed there around and formed integral with the primary catheter bodies.
The patents issued to Bielinski (U.S. Pat. No. 3,437,088), Schlesinger (U.S. Pat. No. 3,805,794), Thow (U.S. Pat. No. 4,057,065), Frisch (U.S. Pat. No. 4,100,246), McWhorter (U.S. Pat. No. 4,106,509), Kenigsberg (U.S. Pat. No. 4,168,703), Betancourt (U.S. Pat. No. 4,180,076) and Ross (U.S. Pat. No. 3,885,567) all relate to catheters for entry into internal body organs such as the stomach and all disclose a multi-lumen apparatus or device. Bielinski discloses a lumen arrangement of four tubes, Schlesinger discloses a central lumen with a smaller lumen, Thow discloses four lumens of differeing diameters vertically arranged within a spotty portion, Frisch also discloses four vertically arranged lumens of differing diameters, McWhorter relates to a balloon catheter having two lumens, Kenigsberg discloses a gastroesophaged reflux diagnostic tool having three lumens, Betancourt provides a nasogastric catheter having three lumens, and finally Ross teaches the use of a gastrointestinal aspirator pump having as many as four lumens in one embodiment.
The patents issued to Shepherd et al (U.S. Pat. No. 3,695,921), Khalil (U.S. Pat. No. 3,359,974), Delgardo (U.S. Pat. No. 3,640,269), Grimsrud (U.S. Pat. No. 4,203,436), and Sagae et al all relate to multi-passageway catheters or other similar devices.
The search was made in Class 128, subclasses 214, 214.2, 214.4, 347, 348, 349R and 349B.
None of the prior art patents uncovered in the search, sets forth a catheter suitable for insertion through the center of the needle into the vein of a patient wherein each lumen is capable of normal fluid flow (i.e., comparable to the flow of fluids through a single lumen catheter). The Howes catheter set forth above does have a number of lumens and can be inserted through the inside of an insertion needle. Howes, however, uses lumens with small fluid passageways which do not compare to the fluid flows in conventional single lumen catheters. A conventional single lumen venous catheter has an internal fluid passageway with a diameter comparable to the inner diameter of the insertion needle. Hence, a single lumen venous catheter has what is termed a "normal" fluid carrying capacity. The Howes' multi-lumen catheter has a number of lumens having passageways with reduced diameters and, therefore, the fluid flow rate is significantly reduced over the normal flow rate of a single lumen catheter. It is to be understood that insertion needles and conventional single lumen venous catheters come in different sized passageways.
It is desired to achieve a multi-lumen catheter which is capable of insertion through conventional insertion needles and yet, after insertion each lumen is capable of fluid carrying capacity comparable to that of a single lumen catheter.
It is therefore an object of the present invention to provide a collapsible multi-lumen catheter which, like a conventional single lumen catheter, is capable of insertion through the center of an insertion needle into the vein of a patient. Yet, after insertion, each lumen is capable of carrying fluid in flow rates comparable to that of conventional single lumen catheters. This is accomplished in the present invention by having a plurality of collapsible lumens disposed around a central flexible lumen wherein each collapsible lumen expands outwardly under the pressure of fluid flow and when fluid flow is absent, the lumen collapses to a smaller cross-sectional area. None of the prior art patents set forth a catheter utilizing collapsible lumens which expand under the pressure of fluid flow after insertion into the patient.